For example, a refrigeration cycle apparatus that uses a refrigeration cycle basically includes a compressor, a condenser, an expansion valve (pressure reducing device), and an evaporator that are connected by refrigerant pipes to form a refrigerant circuit through which refrigerant is circulated. In the refrigeration cycle apparatus, a refrigerant in liquid form (liquid refrigerant or refrigerant liquid) condensed in the condenser has its pressure reduced by the expansion valve, and thus turns into a refrigerant in a two-phase gas-liquid state containing both a refrigerant in gaseous form (gas refrigerant or refrigerant vapor) and a liquid refrigerant. The two-phase gas-liquid refrigerant then enters the evaporator. When refrigerant enters the evaporator in a two-phase gas-liquid state, for example, the resulting deterioration of distribution characteristics in the heat exchanger or other factors cause the energy efficiency of the refrigeration cycle apparatus to decrease.
An approach commonly employed in related art to address this problem is to improve distribution characteristics in the evaporator by adjusting the internal structure of a header that distributes refrigerant to heat transfer tubes or other components, such as by adjusting the amount of protrusion of branch pipes into the header or providing divider plates or ejection holes inside the header (see, for example, Patent Literature 1).
Further, an example of a method to change the state of refrigerant routed into the header involves using a float valve to cause refrigerant in a single, gaseous phase to be routed into the header for distribution, thus improving distribution characteristics (see, for example, Patent Literature 2).